On Sat, Dec 13, 2008 at 11:58:15AM +0200, Lukas Hejtmanek wrote:
> On Sat, Dec 13, 2008 at 09:21:15AM +0800, Wu Fengguang wrote:
> > I cannot reproduce it on 2.6.28-rc7, compiling 2.6.28-rc8...
> > 
> > # free; echo 3 > /proc/sys/vm/drop_caches; free
> >              total       used       free     shared    buffers     cached
> > Mem:          1940        109       1831          0          0         42
> > -/+ buffers/cache:         66       1873
> > Swap:            0          0          0
> >              total       used       free     shared    buffers     cached
> > Mem:          1940         62       1877          0          0          7
> > -/+ buffers/cache:         55       1884
> > Swap:            0          0          0
> > 
> > > once the whole memory is eaten by the cache, the system is pretty unusable.
> > 
> > What's your kconfig?
> 
> attached.
> 
> -- 
> Lukáš Hejtmánek

>Content-Description: ATT14990.config

No drop_caches still works properly here with your kconfig:

# free; echo 3 > /proc/sys/vm/drop_caches; free
             total       used       free     shared    buffers     cached
Mem:          1969        201       1768          0          0         50
-/+ buffers/cache:        151       1818
Swap:            0          0          0
             total       used       free     shared    buffers     cached
Mem:          1969        169       1800          0          0         19
-/+ buffers/cache:        150       1819
Swap:            0          0          0

Lukas, could you apply the attached patch, recompile and do

modprobe filecache
free; cp /proc/filecache /tmp/a;
echo 3 > /proc/sys/vm/drop_caches
free; cp /proc/filecache /tmp/b;

and send me the outputs a and b?

Thanks,
Fengguang